Scroll fluid machine

ABSTRACT

In the scroll fluid machine in which an orbiting scroll  10  is pivot-driven by a rotary shaft  102  rotatably supported by the casing  100  and a pivot shaft  104  eccentrically and rotatably supported by the rotary shaft  102 , as a method, a self-rotation prevention board  109  is attached to one end of the pivot shaft  104  and a self-rotation prevention pin  110  is attached to the self-rotation prevention board  109 . The self-rotation prevention pin  110  is configured to perform an orbiting motion while keeping in contact with the inner surface of the self-rotation prevention bearing (guide body)  111 . Further, as another method, the outer periphery of one end  104   b  of the pivot shaft is configure to perform an orbiting motion while keeping in contact with the inner surface of the balance bearing (guide body)  51 . Based on these methods, an eccentrically pivot driven orbiting scroll performs an orbiting motion without whirling, and thus a high-speed operation of the scroll fluid machine is enabled.

PRIORITY

This application claims priority to International application No.PCT/JP2008/073096 filed Dec. 18, 2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an eccentrically-orbiting-drivingscroll fluid machine.

2. Description of the Related Art

A scroll fluid machine has a work part configured with combination of afixed scroll having a spiral wrap on a paneling and a similar orbitingscroll. The aforementioned orbiting scroll is fixed to the shaft of adrive device and is driven to perform an orbiting motion withoutself-rotation, thereby the working fluid entering through an inlet tubeis compressed and discharged through an outlet tube, and thus the scrollfluid machine functions as a compressor or a blower. If thehigh-pressure working fluid entering through the entrance of the fixedscroll is expanded and discharged through an exit, then the scroll fluidmachine functions as an expander taking power from the shaft of thedrive device.

An eccentrically-orbiting drive device, which has a pivot shaft, isproposed as a drive device used for a scroll fluid machine. For example,the scroll fluid machine as described in Japanese patent No.JP,3761503,B (20.1.2006) includes an eccentrically-orbiting drive deviceand a fluid machine body that is driven by the eccentrically-orbitingdrive device. The pivot shaft of the aforementionedeccentrically-orbiting drive device is passing through the orbitingscroll of the fluid machine body and attached thereto. A first and asecond eccentrically-orbiting support means are provided at both sidesof the aforementioned orbiting scroll, supporting the pivot shaft suchthat the pivot shaft can perform an eccentrically-orbiting motion withrespect to the fixed scroll of the aforementioned fluid machine body.

DISCLOSURE OF THE INVENTION 1. Problems to be Solved by the Invention

In this scroll fluid machine, a pivot shaft bearing supporting a pivotshaft is provided at both sides of an orbiting scroll. A rotary shaftbearing is provided at the outside of both pivot shaft bearings via arotational body having the same axis line as the rotary shaft ofeccentrically-orbiting drive device. As such, when the rotary shaftbearing is driven by the pivot shaft during operation, rotationalresistance caused by the rotary shaft bearing and the pivot shaftbearing is applied in the moving direction of the pivot shaft without amechanism of synchronizing the rotation of both pivot shafts. Thereby, asmooth drive of the pivot shaft is prevented, and thus correspondingwraps have contact with each other, possibly making noise or causingwear or welding of wraps. An object of the present invention is toprevent whirling while keeping a smooth drive of the pivot shaft andprovide a configuration of preventing contact between correspondingwraps, occurrence of noise, and wear or welding of wraps.

2. Means for Solving the Problems

The present invention is to solve the aforementioned problems. One ofthe most important aspects of the present invention is to provide areliable scroll fluid machine that prevents corresponding wraps fromhaving contact with each other, which causes occurrence of vibrationnoise, wear or welding of wraps, with a configuration having littleresistance in the moving direction. Thus, provided is a means forpreventing the pivot shaft from being radially displaced even if therotation speeds up and a centrifugal force of the orbiting scroll isincreased or the differential pressure between the outlet pressure andthe inlet pressure is increased and the load radially applied to thepivot shaft is increased.

In the present invention, a fluid machine comprises: a pivot shafteccentrically and rotatably supported by a rotary shaft; a self-rotationprevention means for preventing the self-rotation of the pivot shaft;and a work part configured with combination of an orbiting scroll,fitted in a pivot drive part of the pivot shaft, having spiral wraps onboth surfaces, and a pair of fixed scrolls fixed to one end of thecasing; wherein the pivot shaft passes through the work part, a fixedscroll located at the most outer part has a guide body, and one end ofthe pivot shaft performs an orbiting motion guided by the guide body,and thus a load is generated so as to cancel the load radially appliedto the pivot shaft. As such, the orbiting scroll is prevented from beingdisplaced or inclined more than the given orbit radius. The guide bodyis a self-rotation prevention guide or a balance bearing attached to thefixed scroll at the most outer side. The self-rotation prevention guideguides the self-rotation prevention pins attached to more than twolocations of the self-rotation prevention board that is attached to thetip of the pivot shaft. The balance bearing guides the tip of the pivotshaft.

3. Effect of the Invention

According to the scroll fluid machine of the present invention, one endof said pivot shaft performs an orbiting motion guided by said guidebody, thereby a load is radially applied to the pivot shaft. The guidebody generates a load, which can cancel the load radially applied to thepivot shaft. Thereby, the orbiting scroll is prevented from beingdisplaced or inclined more than the given orbit radius. Further, even ifthe centrifugal force of the orbiting scroll is increased when thescroll fluid machine is driven at high-speed rotation, the wraps of theorbiting scroll and the fixed scroll are prevented from having contactwith each other, thereby vibration noise, wear or welding of the wrapsare prevented. Therefore, high-reliability scroll fluid machine can beprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an axis-direction cross-sectional view illustrating a firstembodiment.

FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1.

FIG. 3 is a partial cross-sectional view illustrating a modified exampleof the first embodiment.

FIG. 4 is an axis-direction cross-sectional view illustrating anothermodified example of the first embodiment.

FIG. 5 is an axis-direction cross-sectional view illustrating a secondembodiment.

FIG. 6 is a cross-sectional view taken along line A-A in FIG. 5.

FIG. 7 is a partial cross-sectional view illustrating a modified exampleof the second embodiment.

FIG. 8 is an axis-direction cross-sectional view illustrating a thirdembodiment.

FIG. 9 is an axis-direction cross-sectional view illustrating a fourthembodiment.

FIG. 10 is an axis-direction cross-sectional view illustrating a fifthembodiment.

FIG. 11 is an axis-direction cross-sectional view illustrating a sixthembodiment.

FIG. 12 is an axis-direction cross-sectional view illustrating a seventhembodiment.

FIG. 13 is an axis-direction cross-sectional view illustrating amodified example of the seventh embodiment.

FIG. 14 is a view illustrating a state in which scroll wraps arecombined in FIG. 13.

FIG. 15 is an axis-direction cross-sectional view illustrating an eighthembodiment.

FIG. 16 is an axis-direction cross-sectional view illustrating amodified example of the eighth embodiment.

FIG. 17 is an axis-direction cross-sectional view illustrating a ninthembodiment.

FIG. 18 is an axis-direction cross-sectional view illustrating a tenthembodiment.

FIG. 19 is an axis-direction cross-sectional view illustrating amodified example of the tenth embodiment.

FIG. 20 is an axis-direction cross-sectional view illustrating amodified example of the ninth embodiment or the tenth embodiment.

FIG. 21 is an axis-direction cross-sectional view illustrating aneleventh embodiment.

FIG. 22 is a partial cross-sectional view illustrating a first exampleof a joint part between an orbiting scroll and orbiting drive shaft.

FIG. 23 is a partial cross-sectional view illustrating a second exampleof a joint part between an orbiting scroll and orbiting drive shaft.

FIG. 24 is a partial cross-sectional view illustrating a third exampleof a joint part between an orbiting scroll and orbiting drive shaft.

FIG. 25 is a partial cross-sectional view illustrating a part ofself-rotation prevention bearing in a twelfth embodiment.

FIG. 26 is a partial cross-sectional view illustrating a part of balancebearing in a twelfth embodiment.

FIG. 27 is an axis-direction cross-sectional view illustrating athirteenth embodiment.

DESCRIPTION OF SYMBOLS

-   1 first fixed scroll-   2 second fixed scroll-   3 third fixed scroll-   3 g heat insulating plate-   4 fourth fixed scroll-   5 fifth fixed scroll-   6 sixth fixed scroll-   10 orbiting scroll-   11 first orbiting scroll-   12 second orbiting scroll-   13 third orbiting scroll-   14 fourth orbiting scroll-   36 vent hole-   50 bearing block-   51 balance bearing (guide body)-   51 a first balance bearing (guide body)-   51 b second balance bearing (guide body)-   52 balance bearing inner race-   52 a first balance bearing inner race-   52 b second balance bearing inner race-   53 cylinder member-   60 self-rotation prevention board-   61 self-rotation prevention pin-   62 self-rotation prevention bearing (self-rotation prevention guide)-   63 self-rotation prevention bearing inner race-   64 self-rotation prevention slide member (self-rotation prevention    guide)-   71 outlet-   84 inlet-   85 exhaust outlet-   100 casing-   101 rotary shaft bearing-   102 rotary shaft-   103 pivot shaft bearing-   104 pivot shaft-   104 a pivot drive part-   104 b one end of pivot shaft-   104 c another end of pivot shaft-   104 d second pivot drive part-   107 inlet-   108 outlet-   109 self-rotation prevention board-   110 self-rotation prevention pin-   111 self-rotation prevention bearing (guide body)-   112 self-rotation prevention bearing inner race-   113 outlet cover-   114 outlet chamber-   115 self-rotation prevention slide member (guide body)-   116 cylinder member-   117 cover-   207 a compressor inlet-   207 b expander entrance-   208 a compressor outlet-   208 b expander exit-   307 blower inlet-   308 blower outlet

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

FIG. 1 shows a first embodiment. FIG. 2 is a cross-sectional view takenalong line A-A in FIG. 1. The opposite face of wraps of a first fixedscroll 1 in which a paneling has spiral wraps are fixed to a casing 100.An orbiting scroll 10 in which a paneling has spiral wraps is providedon the first fixed scroll 1, and a second fixed scroll 2 in which apaneling has spiral wraps is provided on the orbiting scroll 10 andfixed to the first fixed scroll 1. The first fixed scroll 1, theorbiting scroll 10 and the second fixed scroll 2 constitute a work part.First fixed scroll wraps 1 a and orbiting scroll wraps 10 a provided onthe orbiting scroll 10 are combined to constitute a set of first workchambers 21. Orbiting scroll wraps 10 b provided on the orbiting scroll10 and second fixed scroll wraps 2 a are combined to constitute a set ofsecond work chambers 22.

An outer race of the rotary shaft bearing 101 is provided at twopositions of the casing 100. The rotary shaft 102 is fitted in an innerrace of the rotary shaft bearing 101. A stator 105 of a motor is fixedto the casing 100 and a rotor 106 of the motor is fixed to the rotaryshaft 102. A balancer 47 for balancing the whole centrifugal forces isprovided on the rotary shaft 102. Bearing housing is provided at bothends of the rotary shaft 102, eccentrically located from the center ofrotation. The outer race of the pivot bearing 103 is provided in thebearing housing. The pivot shaft 104 is fitted in the inner race of thepivot bearing 103. The pivot shaft 104 passes through a first fixedscroll through-hole 1 c. A hole is provided in the center of theorbiting scroll 10. The hole is fitted to a pivot drive part 102 awithout relative rotation therebetween. One end of the pivot shaft 104 bpasses through a second fixed scroll through-hole 2 c, extendingoutside. A self-rotation prevention board 109 is fixed to one end of thepivot shaft 104 b. As shown in FIG. 2, a self-rotation prevention pin110 is embedded at three locations on the inner side of theself-rotation prevention board 109. A self-rotation prevention bearing(guide body) 111 is provided on the front side of the second fixedscroll 2 as a self-rotation prevention guide. The self-rotationprevention board 109, self-rotation prevention pin 110 and theself-rotation prevention bearing (guide body) 111 constitute aself-rotation prevention means. The self-rotation prevention pin 110 isincorporated keeping in contact with the inner race 112 of theself-rotation prevention bearing. If the outer diameter of theself-rotation prevention pin 110 is defined as d1, the inner diameter ofthe inner race 112 of the self-rotation prevention bearing is defined asD1 and the orbit radius of the pivot shaft 104 when this fluid machineis driven, is defined as ε and the inner gap of the bearing is definedas δ, then d1, D1, ε and δ are determined so as to satisfy the followingequation:

2ε−δ≦D1−d1≦2ε+δ  (Formula 1)

If the value of D1−d1 is determined as described above, theself-rotation prevention pin 110 can keep substantially in contact withthe inner race 112 of the self-rotation prevention bearing, and therebyself-rotation of the pivot shaft 104 can be securely prevented. Further,one end 104 b of the pivot shaft cannot be bent inward by a strongforce. As such, noise does not occur and machine loss is reduced. Oneend 104 b of the pivot shaft, even if a centrifugal force of theorbiting scroll 10 is applied to the pivot drive part 104 a, does notbend further once the bearing inner gap of self-rotation preventionbearing (guide body) 111 becomes zero. Thereby, contact of scroll wrapscan be prevented. As such, the scroll fluid machine, having even a largeorbiting scroll, can rotate at high speed faster than conventionalmachines.

An outlet cover 113 is fixed to the outer face of second fixed scroll 2,sealing an outlet chamber 114. The outlet cover 113 encloses aself-rotation prevention board 109 and the self-rotation preventionbearing (guide body) 111. An outlet 108 is provided on the outlet cover113. An inlet 107 is provided on the outer periphery of the second fixedscroll 2.

Next, operation of this scroll fluid machine is described. When windingsof the stator 105 are energized, the rotor 106 rotates, thereby therotary shaft 102 rotates such that the pivot shaft 104 is driveneccentrically, self-rotation being prevented as described below. Thepivot drive part 104 a, being a part of the pivot shaft 104 pivot drivesthe orbiting scroll 10. The first work chamber 21 including the firstfixed scroll wrap 1 a and the orbiting scroll wrap 10 a and the secondwork chamber 22 including the second fixed scroll wrap 2 a and theorbiting scroll wrap 10 b move from the outer periphery side to theinner periphery side, and thus the volume is decreased, causing theinside fluid to be compressed. An orbiting paneling communication hole10 c is provided at the center part of the paneling of the orbitingscroll 10. As such, the work chamber 21 and the work chamber 22 arecommunicated at the center part. As a result, fluid is taken in throughthe inlet 107, compressed through an intake chamber 130, jointly flowninto the work chamber 22, flown into the outlet chamber 114 through asecond fixed scroll through-hole 2 c, and discharged to the outside fromthe outlet 108.

Based on Formula 1 showing the relationships among the outer diameter d1of the self-rotation prevention pin 110, the inner diameter D1 of theinner race 112 of the self-rotation prevention bearing and the orbitradius ε, the self-rotation prevention pin 110 performs an orbitingmotion while applying a certain contact force constantly to the innerrace 112 of the self-rotation prevention bearing. The self-rotationprevention board 109 performs an orbiting motion, however cannot rotatedue to the self-rotation prevention pin 110 provided at two or morelocations of the self-rotation prevention board 109. The self-rotationprevention board 109 is fixed to one end 104 b of the pivot shaft 104,thereby the pivot shaft 104, being prevented from self-rotating,performs an orbiting motion. Further, the orbiting scroll 10, fitted inthe pivot drive part 104 a without relative rotation, is prevented fromself-rotating and performs an orbiting motion.

Further, since the orbiting scroll 10 has mass, a centrifugal forceoccurs in an orthogonal direction to the shaft when the orbiting scroll10 performs an orbiting motion. The whole centrifugal force is canceledby the balancer 47. However, the centrifugal force applies a load to theshaft such that the orbiting scroll is radially displaced. This loadworks to bend the pivot drive part 104 a. The pivot drive part 104 a isbent in the direction of a synthetic load around the pivot bearing 103as a fulcrum point. As a result, the orbiting scroll 10 is also benttoward the synthetic load while being displaced. Thereby, orbitingscroll wraps 10 a and 10 b come close to the first fixed scroll wrap 1 aand the second fixed scroll wrap 2 a. When wraps come close to eachother, gaps between the wraps, which are initially set to be small tominimize a leak, becomes zero, and triggering a slide. Thereby, slideloss occurs in wraps. Further, vibration noise occurs in the scrollfluid machine. Additionally, wear of wraps is increased, welding occursbetween wraps, and so on. That is, both performance and reliability ofthe scroll fluid machine are lost.

However, according to the present invention, the self-rotationprevention pin 110 having contact with the self-rotation preventionbearing inner race 112, one end of the pivot shaft 104 b cannot bedisplaced more than the orbit radius determined by the self-rotationprevention pin 110 and the self-rotation prevention bearing inner race112.

Accordingly, even if the orbiting scroll 10 rotates at high speed, acentrifugal force is increased and thus a load bending the pivot drivepart 104 a becomes large, deflection of the pivot drive part 104 a isprevented. As such, wraps do not contact each other. Therefore, thescroll fluid machine according to the present invention, can realizehigh-speed rotation compared to the conventional machines even if thescroll fluid machine has a large orbiting scroll.

FIG. 3 is a partial cross-sectional view illustrating a modified exampleof the first embodiment. As shown in FIG. 3, a self-rotation preventionslide member (guide body) 115 is used as a self-rotation preventionguide instead of the self-rotation prevention bearing (guide body) 111.The self-rotation prevention board 109, the self-rotation prevention pin110 and the self-rotation prevention slide member (guide body) 115constitute a self-rotation means. The self-rotation prevention slidemember (guide body) 115 is made of self-lubricating material such asresin. The self-rotation prevention pin 110, which is in contact withand guided by the inner surface of the self-rotation prevention slidemember (guide body) 115, performs an orbiting motion, thereby theself-rotation of the pivot shaft 104 and the orbiting scroll 10 isprevented while one end of pivot shaft 104 b cannot be displaced morethan the orbit radius determined by the self-rotation prevention pin 110and the self-rotation prevention slide member (guide body) 115.

In this way, the self-rotation prevention pin 110 and the self-rotationprevention slide member (guide body) 115 are in contact with each other,and thus the self-rotation of the orbiting scroll can be securelyprevented. Further, even if the centrifugal force of the orbiting scroll10 is applied to the pivot drive part 104 a, one end of pivot shaft 104b does not bend further after the self-rotation prevention pin 110 andthe self-rotation prevention slide member (guide body) 115 come intocontact. As such, contact between wraps can be prevented. Accordingly,the scroll fluid machine according to the present invention can performan orbiting motion faster and more accurate than conventional machines,even with a large orbiting scroll.

FIG. 4 shows another modified example of the first embodiment. FIG. 4shows an example of cooling with a fan 31 provided at the back end 102 aof the rotary shaft when the first embodiment is used as a vacuum pump.A bearing board 35 is provided with a through-hole as a vent hole. Anexhaust outlet 34 is provided on the lateral face of the casing 100closer to the first fixed scroll 1 than the stator 105. The pivot shaft104 is provided with a through-hole as a pivot shaft vent hole 32. Abottom plate 100 a of the casing 100 has an opening to which a filter 30is attached. When the fan 31 rotates together with the rotary shaft 102,air is taken in from the outside via the filter 30. The air enteringthrough the filter 30 flows through a motor part space 33 in the casing100 through the vent hole 36 and is exhausted to the outside through theexhaust outlet 34. In the mean time, the rotary shaft bearing 101 andthe stator 105 are cooled down and are prevented from raisingtemperature excessively.

Further, air entering through the filter 30 flows out of the fan 31 andflows in an outlet chamber 114 through a pivot shaft vent hole 32, andis exhausted to the outside through the outlet 108 along with the airexhausted from a first work chamber 21 and a second work chamber 22. Inthe meantime the center part of the pivot bearing 101 and the orbitingscroll 10 is cooled down, thereby excessive temperature rise isprevented.

Further, FIG. 4 shows an example of a seal member provided to seal spacebetween the work chamber side and the casing side when the firstembodiment according to the present invention is used as a vacuum pump.A ring-shaped inner face seal 42 is attached so as to surround a firsfixed scroll through-hole 1 c. A seal board 40 is in contact with theinner face seal 42 and attached to the pivot shaft 104. A seal cover 41is attached to the casing side facing the seal board 40. A ring-shapedouter face seal 43 is attached to a seal cover 41, and is in contactwith the seal board 40. Based on this configuration, space on the sideof the work chamber and space on the side of the casing are doublesealed sandwiching the first fixed scroll through-hole 1 c. Thus, theexhausted gas from the work chamber is securely prevented from leakinginto inside of the casing. Further, the exhausted gas is shut out fromoutside air by the outlet cover 113 and is discharged through an outsideduct (not shown) connected to the outlet 108. Therefore, noxious orcorrosive gas does not leak into outside air even though it may flow inthe work chamber.

Second Embodiment

FIG. 5 shows a second embodiment. FIG. 6 is a cross-sectional view takenalong line A-A. The same parts as those in the first embodiment employthe same symbols and names and the description is not repeated. Theoutlet cover 113 is attached to the outside face of the paneling of thesecond fixed scroll 2. A balance bearing (guide body) 51 is attached tothe inside of the outlet cover 113. The outer periphery of one end 104 bof the pivot shaft performs an orbiting motion while keeping in contactwith the inner race 52 of the balance bearing. If the outer diameter ofone end 104 b of the pivot shaft is defined as d2, the inner diameter ofthe inner race 52 of the balance bearing is defined as D2 and the orbitradius of the pivot shaft 104 when this scroll fluid machine is driven,is defined as ε and an inner gap of the bearing is defined as δ, thend2, D2, ε and δ are determined so as to satisfy the following equation:

2ε−δ≦D2−d2≦2ε+δ  (Formula 2)

If the value of D2−d2 is determined as described above, one end 104 b ofthe pivot shaft can keep substantially in contact with the inner race 52of the balance bearing. Further, one end 104 b of the pivot shaft cannotbe bent inward by a strong force. As such, noise hardly occurs andmachine loss is reduced. One end 104 b of the pivot shaft, even if acentrifugal force of the orbiting scroll 10 is applied to the pivotdrive part 104 a, does not bend further when the bearing inner gap ofbalance bearing (guide body) 51 becomes zero. Thereby, contact of scrollwraps can be prevented. As such, the scroll fluid machine, having even alarge orbiting scroll, can rotate at high speed faster than conventionalmachines.

A self-rotation prevention board 60 is fixed to another end 104 c of thepivot shaft. The self-rotation prevention pin 61 is embedded in morethan two locations of the self-rotation prevention board 60. Aself-rotation prevention bearing 62 is attached to the bottom plate 100a of the casing 100. The self-rotation prevention pin 61 performs anorbiting motion while keeping in contact with an inner race 63 of theself-rotation prevention bearing.

If the outer diameter of the self-rotation prevention pin 61 is definedas d3, the inner diameter of the inner race 63 of the self-rotationprevention bearing is defined as D3 and the orbit radius of the pivotshaft 104 when this fluid machine is driven, is defined as ε and aninner gap of the bearing is defined as δ, then d3, D3, ε and δ aredetermined so as to satisfy the following equation:

2ε−δ≦D3−d3≦2ε+δ  (Formula 3)

If the value of D3−d3 is determined as described above, theself-rotation prevention pin 61 can keep substantially in contact withthe inner race 63 of the self-rotation prevention bearing. Thus, theself-rotation of the orbiting scroll 10 can be securely prevented.Further, another end 104 c of the pivot shaft cannot be bent inward by astrong force. As such, noise hardly occurs and machine loss is reduced.

FIG. 7 shows a modified example of the second embodiment. As shown inFIG. 7, one end 104 b of the pivot shaft is barrel shaped, having acurved surface along the axis direction. This can prevent one end 104 bof the pivot shaft from having partial contact with the inner race 52 ofthe balance bearing. As such, the contact surface between one end 104 bof the pivot shaft and the inner race 52 of the balance bearing isprevented from causing scoring and galling. Therefore, reliability ofthe scroll fluid machine is improved. Further, a self-rotationprevention slide member 64 is used as a guide of the self-rotationprevention pin 61 attached to the self-rotation prevention board 60. Theself-rotation prevention slide member 64 is formed of self-lubricatingmaterial such as resin. The self-rotation prevention slide member 64 maybe formed of metal material, to which wear-resistance surface treatmentis applied.

Third Embodiment

FIG. 8 shows a third embodiment. A cover 70 seals outer surface of thecenter part of the second fixed scroll 2, insulating the work chamberfrom outside air. Further, an outlet 71 is provided on the bottom sidewith respect to a stator 105 at the outer periphery of the casing 100.Fluid flowing through an inlet 107, is compressed in the first workchamber 21 and the second work chamber 22, flows in the casing 100through the first fixed scroll through-hole 1 c, and is discharged tothe outside through the outlet 71 after passing through the inside ofthe casing 100. According to this configuration, the simply formed cover70 can be used instead of outlet cover 113. As such, one work piece canbe saved in the scroll fluid machine, thereby cost can be reduces.Further the total length can be shortened without projections. Also, theinside of the casing can be cooled down by circulating working fluid.

Fourth Embodiment

FIG. 9 shows a fourth embodiment. The fluid machine shown in FIG. 9 is atwin-type scroll fluid machine, which has scrolls at both ends of thepivot shaft 104. The opposite face of wraps of the first fixed scroll 1is fixed to the right side of the casing 100. A first orbiting scroll 11is provided over the first fixed scroll 1. The second fixed scroll 2 isprovided over the first orbiting scroll 11 and is fixed to the firstfixed scroll 1. The first fixed scroll 1, the first orbiting scroll 11and the second fixed scroll 2 constitute a work part at one end of thepivot shaft.

The first fixed scroll wrap 1 a and the first orbiting scroll wrap 11 aare combined to constitute a set of first work chambers 21. The firstorbiting scroll wrap 11 b and the second fixed scroll wrap 2 a arecombined to constitute a set of second work chambers 22. A firstorbiting paneling communication hole 11 c is provided in the center ofthe paneling of the first orbiting scroll 11. Thereby, the first workchamber 21 is communicated with the second work chamber 22 through thefirst orbiting paneling communication hole 11 c. As a result, fluid istaken in through a first inlet 107 a, is compressed through a firstintake chamber 131, jointly flows into the work chamber 22, flows intothe outlet chamber 114 a in a first outlet cover 113 a through a secondfixed scroll through-hole 2 c, and discharged to the outside from theoutlet 108 a.

The opposite face of wraps of the third fixed scroll 3 is fixed to theleft side of the casing 100. A second orbiting scroll 12 is providedover the third fixed scroll 3. The fourth fixed scroll 4 is providedover the second orbiting scroll 12 and is fixed to the third fixedscroll 3. The third fixed scroll 3, the second orbiting scroll 12 andthe fourth fixed scroll 4 constitute a work part at another end of thepivot shaft. The third fixed scroll wrap 3 a and the second orbitingscroll wrap 12 a are combined to constitute a set of third work chambers23. The second orbiting scroll wrap 12 b and the fourth fixed scrollwrap 4 a are combined to constitute a set of fourth work chambers 24.

The rotary shaft 102 rotates and the pivot shaft 104 is eccentricallydriven without self-rotation. A second pivot drive part 104 d, being apart of the pivot shaft 104, pivot drives the orbiting scroll 12.Working fluid moves from the outer periphery to the inner periphery ofthe third work chamber 23 and the fourth work chamber 24 and the volumeis decreased and compressed.

A second orbiting paneling communication hole 12 c is provided in thecenter part of the paneling of the second orbiting scroll 12. Thereby,the third work chamber 23 is communicated with the fourth work chamber24 through the second orbiting paneling communication hole 12 c. As aresult, working fluid taken in through a second inlet 107 b, iscompressed through a second intake chamber 132, passes through thefourth fixed scroll through-hole 4 c, flows into the second outletchamber 114 b in a second outlet cover 113 b through a second fixedscroll through-hole 2 c, and discharged to the outside from the secondoutlet 108 b.

The outer race of the rotary shaft bearing 101 is provided at twolocations in the casing 100. The rotary shaft 102 is fitted in the innerrace of the rotary shaft bearing 101. A balancer 47 is attached at twolocations of the rotary shaft 102 to keep a balance of the wholecentrifugal forces. The stator 105 of a motor is fixed to the casing 100and the rotor 106 of the motor is fixed to the rotary shaft 102. Abalancer 47 for balancing the whole centrifugal forces is provided onthe rotary shaft 102. Bearing housing is provided at both ends of therotary shaft 102, eccentrically located from the center of rotation. Theouter race of the pivot bearing 103 is provided in the bearing housing.The pivot shaft 104 is fitted in the inner race of the pivot bearing103. The pivot shaft 104 passes through the first fixed scrollthrough-hole 1 c. A hole is provided in the center of the first orbitingscroll 11. The hole is fitted to a pivot drive part 104 a withoutrelative rotation therebetween. One end of the pivot shaft 104 b passesthrough the second fixed scroll through-hole 2 c, extending outside. Theself-rotation prevention board 109 is fixed to one end of the pivotshaft 104 b. As shown in FIG. 2, a self-rotation prevention pin 110 isembedded at three locations on the inner side of the self-rotationprevention board 109. A self-rotation prevention bearing (guide body)111 is provided on the front side of the second fixed scroll 2. Theself-rotation prevention pin 110 is incorporated keeping in contact withthe inner race 112 of the self-rotation prevention bearing. If the outerdiameter of the self-rotation prevention pin 110 is defined as d1, theinner diameter of the inner race 112 of the self-rotation preventionbearing is defined as D1 and the orbit radius of the pivot shaft 104when this fluid machine is driven, is defined as ε and the inner gap ofthe bearing is defined as δ, d1, D1, ε and δ are determined so as tosatisfy the Formula 1.

The pivot shaft 104 passes through the third fixed scroll through-hole 3c. A hole is provided in the center of the second orbiting scroll 12.The hole is fitted to a second pivot drive part 104 d without relativerotation therebetween. Another end 104 c of the pivot shaft passesthrough a fourth fixed scroll through-hole 4 c, extending outside. Abearing block 50 is attached to the outside face of the paneling of thefourth fixed scroll 4. A balance bearing (guide body) 51 is attached tothe inside of the bearing block 50. The outer periphery of another end104 c of the pivot shaft performs an orbiting motion while keeping incontact with the inner race 52 of the balance bearing. If the outerdiameter of another end 104 c of the pivot shaft is defined as d2, theinner diameter of the inner race 52 of the balance bearing is defined asD2 and the orbit radius of the pivot shaft 104 when this scroll fluidmachine is driven, is defined as ε and an inner gap of the bearing isdefined as δ, d2, D2, ε and δ are determined so as to satisfy theFormula 2.

According to this embodiment, as described above, a set of scroll partsis provided at one end of the casing 100 while another set of scrollpart is provided at another end of the casing 100. As such, thisembodiment can produce twice the flow volume compared to a fluid machineprovided with a single set of the scroll part at one end of the casing100. A self-rotation prevention mechanism is provided at one end 104 bof the pivot shaft, on the right side of the pivot shaft 104, Further,relationships among the outer diameter of the self-rotation preventionpin 110 and the inner diameter of the inner race 112 of theself-rotation prevention bearing 112 is determined by the Formula 1.Thus, the self-rotation of the pivot shaft 104 can be securelyprevented. Further, deflection of one end 104 b of the pivot shaft dueto centrifugal force is prevented. The outer periphery of another end104 c of the pivot shaft performs an orbiting motion while keeping incontact with the inner race 52 of the balance bearing.

Further, the relationship between another end 104 c of the pivot shaftand the inner race 52 of the balance bearing is determined by Formula 2.Therefore, deflection of another end 104 c of the pivot shaft due tocentrifugal force is prevented.

Fifth Embodiment

FIG. 10 shows a fifth embodiment. The structure of the drive part is thesame as the fourth embodiment. The same components as the fourthembodiment employ the same symbols and names and the description is notrepeated. A part of this embodiment, which is different than the fourthembodiment, is described. One end 104 b of the pivot shaft passesthrough the through-hole 2 c of the second fixed scroll and extends tooutside. A first outlet cover 113 a is attached to the outside face ofthe paneling of the second fixed scroll 2. A first balance bearing(guide body) 51 a is attached to the inside of the first outlet cover113 a. The outer periphery of one end 104 b of the pivot shaft performsan orbiting motion while keeping in contact with the inner race 52 a ofthe first balance bearing. If the outer diameter of one end 104 b of thepivot shaft is defined as d2, the inner diameter of the inner race 52 aof the first balance bearing is defined as D2 and the orbit radius ofthe pivot shaft 104 when this scroll fluid machine is driven, is definedas ε and an inner gap of the bearing is defined as δ, then d2, D2, ε andδ are determined so as to satisfy Formula 2.

A second outlet cover 113 b is attached to the outside face of thepaneling of the fourth fixed scroll 4. A second balance bearing (guidebody) 51 b is attached to the inside of the second outlet cover 113 b.The outer periphery of another end 104 c of the pivot shaft performs anorbiting motion while keeping in contact with the inner race 52 b of thesecond balance bearing. If the outer diameter of another end 104 c ofthe pivot shaft is defined as d2, the inner diameter of the inner race52 b of the second balance bearing is defined as D2 and the orbit radiusof the pivot shaft 104 when this fluid machine is driven, is defined asε and an inner gap of the bearing is defined as δ, then d2, D2, ε and δare determined so as to satisfy Formula 2.

A self-rotation prevention board 60 is provided between the right sideof the pivot bearing 103 and the paneling of the first fixed scroll 1 toprevent relative rotation therebetween. A self-rotation prevention pin61 is embedded at three locations in the outer periphery of theself-rotation prevention board. A self-rotation prevention bearing 62 isprovided on the paneling of the first fixed scroll 1. A self-rotationprevention pin 61 performs an orbiting motion while keeping in contactwith the inner race 63 of the self-rotation prevention bearing. If theouter diameter of the self-rotation prevention pin 61 is defined as d3,the inner diameter of the inner race 63 of the self-rotation preventionbearing is defined as D3 and the orbit radius of the pivot shaft 104when this fluid machine is driven, is defined as ε and an inner gap ofthe bearing is defined as δ, then d3, D3, ε and δ are determined so asto satisfy Formula 3.

According to this embodiment, as described above, a set of scroll partsis provided at one end of the casing 100 while another set of scrollpart is provided at another end of the casing 100. As such, thisembodiment, similarly to the fourth embodiment according to the presentinvention, can produce twice the flow volume compared to a fluid machineprovided with a single set of the scroll part at one end of the casing100. The outer periphery of one end 104 b of the pivot shaft performs anorbiting motion while keeping in contact with the inner race 52 a of thefirst balance bearing. The relationship between one end 104 b of thepivot shaft and the inner race 52 a of the first balance bearing isdetermined by Formula 2. Therefore, deflection of one end 104 b of thepivot shaft due to centrifugal force is prevented. Further, the outerperiphery of another end 104 c of the pivot shaft performs an orbitingmotion while keeping in contact with the inner race 52 b of the secondbalance bearing. Also, the relationship between another end 104 c of thepivot shaft and the inner race 52 b of the second balance bearing isdetermined by Formula 2. Therefore, deflection of another end 104 c ofthe pivot shaft due to centrifugal force is prevented.

Sixth Embodiment

FIG. 11 shows a sixth embodiment. A first cover 70 a seals outer surfaceof the center part of the second fixed scroll 2, insulating the workchamber from outside air. Further, a second cover 70 b seals outersurface of the center part of the fourth fixed scroll 4, insulating thework chamber from outside air. Further, the outlet 71 is provided on apart of the lateral face of the casing 100. The fluid flowing outthrough the first work chamber 21 and the second work chamber 22 flowsin the casing 100 via the through-hole 1 c of the first fixed scroll.The fluid passes through the inside of the casing 100 and is dischargedto the outside through the outlet 71. According to this configuration,as shown in FIG. 11, the simply formed first cover 70 a and second cover70 b can be used instead of the first outlet cover 113 a and the secondoutlet cover 113 b as shown in FIG. 10. As such, two work pieces can besaved in this structure, thereby cost can be saved while the totallength can be shortened without projections. Also, the inside of thecasing can be cooled down by compressed working fluid.

Seventh Embodiment

FIG. 12 shows a seventh embodiment. FIG. 12 shows a fluid machine inwhich the pivot drive part 104 a includes a pair of scrolls. The samecomponents as the first embodiment employ the same symbols and names andthe description is not repeated. The opposite face of wraps of the firstfixed scroll 1 is fixed to the casing 100. The first orbiting scroll 11is provided over the first fixed scroll 1. The third fixed scroll 3 isprovided over the first orbiting scroll 11 and is fixed to the firstfixed scroll 1. The second orbiting scroll 12 is provided over the thirdfixed scroll 3. The second fixed scroll 2 is provided over the secondorbiting scroll 12 and is fixed to the first fixed scroll 1 togetherwith the third fixed scroll 3. The first fixed scroll 1, the firstorbiting scroll 11, the third fixed scroll 3, the second orbiting scroll12 and the second fixed scroll 2 constitute a work part.

A set of first work chamber 21 is formed with a combination of the firstfixed scroll wrap 1 a and the first orbiting scroll wrap 11 a. A set ofsecond work chamber 22 is formed with a combination of the firstorbiting scroll wrap 11 b and the third fixed scroll wrap 3 a. A set ofthird work chamber 23 is formed with a combination of the third fixedscroll wrap 3 b and the second orbiting scroll wrap 12 a. A set offourth work chamber 24 is formed with a combination of the secondorbiting scroll wrap 12 b and the second fixed scroll wrap 2 a.

An intake communication hole 3 d is provided in the third fixed scroll 3and thus a first intake chamber 131 and a second intake chamber 132 arecommunicated. A first orbiting paneling communication hole 11 c isprovided in the center part of the paneling of the first orbiting scroll11. Thereby, the first work chamber 21 is communicated with the secondwork chamber 22 through the first orbiting paneling communication hole11 c. A second orbiting paneling communication hole 12 c is provided inthe center part of the paneling of the second orbiting scroll 12.Thereby, the third work chamber 23 is communicated with the fourth workchamber 24 through the second orbiting paneling communication hole 12 c.Therefore, fluid is taken into every work chamber and is discharged tothe outside through the outlet 108.

The pivot shaft 104 passes through the first fixed scroll through-hole 1c. A hole is provided in the center of the first orbiting scroll 11. Thehole is fitted to the pivot drive part 104 a without relative rotation.The pivot shaft 104 passes through the third fixed scroll through-hole 3c. A hole is provided in the center of the second orbiting scroll 12.The hole is fitted to the pivot drive part 104 a without relativerotation. One end 104 b of the pivot shaft passes through the secondfixed scroll through-hole 2 c and extends to the outside. An outletcover 113 is attached to the outer surface of the paneling of the secondfixed scroll 2. A balance bearing (guide body) 51 is attached to theinside the outlet cover 113. The outer periphery of one end 104 b of thepivot shaft performs an orbiting motion while keeping in contact withthe inner race 52 of the balance bearing. If the outer diameter of oneend 104 b of the pivot shaft is defined as d2, the inner diameter of theinner race 52 of the balance bearing is defined as D2 and the orbitradius of the pivot shaft 104 when this scroll fluid machine is driven,is defined as ε and an inner gap of the bearing is defined as δ, thend2, D2, ε and δ are determined so as to satisfy Formula 2. Aself-rotation prevention mechanism similarly to the second embodiment isincorporated in another end 104 of the pivot shaft 104 c. Aself-rotation prevention bearing is attached to the bottom board 100 a.The self-rotation prevention pin 61 is maintained substantially incontact with the inner race 63 of the self-rotation prevention bearing.As such, the self-rotation of the pivot shaft 104 is securely prevented.

According to this embodiment, one end 104 b of the pivot shaft and theinner race 52 of the balance bearing are maintained substantially incontact with each other. Thereby, even if the centrifugal force of thefirst orbiting scroll 11 and the second orbiting scroll 12 is applied tothe pivot drive part 104 a, one end 104 b of the pivot shaft is not bentmore when the inner gap of the bearing in the inner race 52 of thebalance bearing becomes zero. As such, contact between wraps isprevented. Further, even if the scroll fluid machine includes a largeorbiting scroll, it can rotate faster than the conventional machines.Further, the scroll fluid machine can produce twice the flow volumecompared to the fluid machine provided with a single set of the scrollat one end of the casing 100.

FIGS. 13 and 14 show an example in which phase is shifted between intakeand discharge in the seventh embodiment. The scroll fluid machine canshift the phase of intake and discharge with respect to eccentricdirection of the pivot shaft by changing rotational direction positionof the wrap when installing the machine. As shown in FIG. 14, incombinations of the first fixed scroll wrap 1 a and the first orbitingscroll wrap 11 a, the third fixed scroll wrap 3 a and the first orbitingscroll wrap 11 b, the third fixed scroll wrap 3 b and the secondorbiting scroll wrap 12 a, and the second fixed scroll wrap 2 a and thesecond orbiting scroll wrap 12 b, the phase of the wraps is shifted by90 degrees respectively. Accordingly, the first orbiting scroll wrap 11a, the first orbiting scroll wrap 11 b, the second orbiting scroll wrap12 a, the second orbiting scroll wrap 12 b are all eccentric toward thesame direction (in the right direction in the drawing). Nevertheless,the phase of the four work chambers is shifted by 90 degreesrespectively.

Eighth Embodiment

FIG. 15 shows an eighth embodiment. The same components as the firstembodiment employ the same symbols and names and the description is notrepeated. The opposite face of wraps of the first fixed scroll 1 isfixed to the right side of the casing 100. The first orbiting scroll 11is provided over the first fixed scroll 1. The third fixed scroll 3 isprovided over the first orbiting scroll 11 and is fixed to the firstfixed scroll 1. The second orbiting scroll 12 is provided over the thirdfixed scroll 3. The second fixed scroll 2 is provided over the secondorbiting scroll 12 and is fixed to the first fixed scroll 1 togetherwith the third fixed scroll 3. The first fixed scroll 1, the firstorbiting scroll 11, the third fixed scroll 3, the second orbiting scroll12 and the second fixed scroll 2 constitute a work part at one end ofthe pivot shaft. A set of first work chamber 21 is formed with acombination of the first fixed scroll wrap 1 a and the first orbitingscroll wrap 11 a. A set of second work chamber 22 is formed with acombination of the first orbiting scroll wrap 11 b and the third fixedscroll wrap 3 a. A first orbiting paneling communication hole 11 c isprovided in the center part of the paneling of the first orbiting scroll11. The first work chamber 21 is communicated with the second workchamber 22 through the first orbiting paneling communication hole 11 c.A set of third work chamber 23 is formed with a combination of the thirdfixed scroll wrap 3 b and the second orbiting scroll wrap 12 a. A set offourth work chamber 24 is formed with a combination of the secondorbiting scroll wrap 12 b and the second fixed scroll wrap 2 a. A secondorbiting paneling communication hole 12 c is provided in the center partof the paneling of the second orbiting scroll 12. The third work chamber23 is communicated with the fourth work chamber 24 through the secondorbiting paneling communication hole 12 c. A third fixed scroll intakecommunication hole 3 d is provided at the third fixed scroll 3, therebythe first intake chamber 131 and the second intake chamber 132 arecommunicated with each other.

Further, the third fixed scroll through-hole 3 c is provided in thecenter part of the third fixed scroll 3, thereby the fluid taken inthrough the first inlet 107 is compressed in the work chamber 21. 22, 23and 24, joins together into the outlet chamber 114 in a first outletcover 113 a and is discharged to the outside from the first outlet 108a.

The opposite face of wraps of the fourth fixed scroll 4 is fixed to theleft side of the casing 100. The third orbiting scroll 13 is providedover the fourth fixed scroll 4. The sixth fixed scroll 6 is providedover the third orbiting scroll 13 and is fixed to the fourth fixedscroll 4. The fourth orbiting scroll 14 is provided over the sixth fixedscroll 6. The fifth fixed scroll 5 is provided over the fourth orbitingscroll 14 and is fixed to the fourth fixed scroll 4 together with thesixth fixed scroll 6. The fourth fixed scroll 4, the third orbitingscroll 13, the sixth fixed scroll 6, the fourth orbiting scroll 14 andthe fifth fixed scroll 5 constitute a work part at another end of thepivot shaft.

A set of the fifth work chamber 25 is formed with a combination of thefourth fixed scroll wrap 4 a and the third orbiting scroll wrap 13 a. Aset of the sixth work chamber 26 is formed with a combination of thethird orbiting scroll wrap 13 b and the sixth fixed scroll wrap 6 a.

A third orbiting paneling communication hole 13 c is provided in thecenter part of the paneling of the third orbiting scroll 13. The fifthwork chamber 25 is communicated with the sixth work chamber 26 throughthe third orbiting paneling communication hole 13 c.

A set of the seventh work chamber 27 is formed with a combination of thesixth fixed scroll wrap 6 b and the fourth orbiting scroll wrap 14 a. Aset of eighth work chamber 28 is formed with a combination of the fourthorbiting scroll wrap 14 b and the fifth fixed scroll wrap 5 a. A fourthorbiting paneling communication hole 14 c is provided in the center partof the paneling of the fourth orbiting scroll 14. Thereby, the seventhwork chamber 27 is communicated with the eighth work chamber 28 throughthe fourth orbiting paneling communication hole 14 c.

A sixth fixed scroll intake communication hole 6 d is provided at thesixth fixed scroll 6, thereby the third intake chamber 133 and thefourth intake chamber 134 are communicated with each other. Further, thesixth fixed scroll through-hole 6 c is provided in the center part ofthe sixth fixed scroll 6, thereby fluid taken in through the secondinlet 107 b is compressed in the work chamber 25. 26, 27 and 28, and isdischarged to the outside from the second outlet 108 b provided at thesecond outlet cover 113 b.

The structure of the drive part is the same as the first embodiment. Thepivot shaft 104 passes through the first fixed scroll through-hole 1 c.A hole is provided in the center of the first orbiting scroll 11 and thesecond orbiting scroll 12. The hole is fitted to the pivot drive part104 a without relative rotation. One end of the pivot shaft 104 passesthrough the second fixed scroll through-hole 2 c and extends to theoutside. A self-rotation prevention board 109 is fixed to one end 104 bof the pivot shaft.

As shown in FIG. 2, a self-rotation prevention pin 110 is embedded atthree locations on the inner side of the self-rotation prevention board109. A self-rotation prevention bearing (guide body) 111 is provided onthe front side of the second fixed scroll 2 as a self-rotationprevention guide.

The self-rotation prevention board 109, self-rotation prevention pin 110and the self-rotation prevention bearing (guide body) 111 constitute aself-rotation prevention means. The self-rotation prevention pin 110 isincorporated keeping in contact with the inner race 112 of theself-rotation prevention bearing. If the outer diameter of theself-rotation prevention pin 110 is defined as d1, the inner diameter ofthe inner race 112 of the self-rotation prevention bearing is defined asD1 and the orbit radius of the pivot shaft 104 when this fluid machineis driven, is defined as ε and the inner gap of the bearing is definedas δ, then d1, D1, ε and δ are determined so as to satisfy Formula 1.

The pivot shaft 104 passes through a fourth fixed scroll through-hole 4c. A hole is provided in the center of the third orbiting scroll 13 andthe fourth orbiting scroll 14. The hole is fitted to a second pivotdrive part 104 d without relative rotation therebetween. Another end 104c of the pivot shaft passes through a fifth fixed scroll through-hole 5c, extending outside. A second outlet cover 113 b is attached to theouter surface of the paneling of the fifth fixed scroll 5. A balancebearing (guide body) 51 is attached to the inside of the outlet cover113. The outer periphery of another end 104 c of the pivot shaftperforms an orbiting motion while keeping in contact with the inner race52 of the balance bearing. If the outer diameter of another end 104 c ofthe pivot shaft is defined as d2, the inner diameter of the inner race52 of the balance bearing is defined as D2 and the orbit radius of thepivot shaft 104 when this scroll fluid machine is driven, is defined asε and an inner gap of the bearing is defined as δ, then d2, D2, ε and δare determined so as to satisfy Formula 2.

This embodiment configured as described above can produce four times aslarge as the flow volume compared to a fluid machine provided with asingle set of the scroll part at one end of the casing 100. Theself-rotation of the pivot shaft 104 is securely prevented by aself-rotation prevention mechanism provided at one end 104 b of thepivot shaft, on the right side of the pivot shaft 104. Further,deflection of one end 104 b of the pivot shaft due to centrifugal forceis prevented. The outer periphery of another end 104 c of the pivotshaft performs an orbiting motion while keeping in contact with theinner race 52 of the balance bearing. The relationship between anotherend 104 c of the pivot shaft and the inner race 52 of the balancebearing is determined by Formula 2. Therefore, deflection of another end104 c of the pivot shaft due to centrifugal force is prevented.

FIG. 16 shows a modified example of an eighth embodiment. The structureof the drive part is the same as the eighth embodiment. The samecomponents as the eighth embodiment employ the same symbols and namesand the description is not repeated. A part of this embodiment, which isdifferent than the eighth embodiment, is described. One end 104 b of thepivot shaft passes through the through-hole 2 c of the second fixedscroll and extends to the outside. A first outlet cover 113 a isattached to the outside face of the paneling of the second fixed scroll2. A first balance bearing (guide body) 51 a is attached to the insideof the first outlet cover 113 a. The outer periphery of one end 104 b ofthe pivot shaft performs an orbiting motion while keeping in contactwith the inner race 52 a of the balance bearing. If the outer diameterof one end 104 b of the pivot shaft is defined as d2, the inner diameterof the inner race 52 a of the first balance bearing is defined as D2 andthe orbit radius of the pivot shaft 104 when this scroll fluid machineis driven, is defined as ε and an inner gap of the bearing is defined asδ, then d2, D2, ε and δ are determined so as to satisfy Formula 2.Therefore, deflection of one end 104 b of the pivot shaft due tocentrifugal force is prevented.

Another end 104 c of the pivot shaft passes through the through-hole 5 cof the fifth fixed scroll and extends to the outside. A second outletcover 113 b is attached to the outside face of the paneling of thesecond fixed scroll 2. A second balance bearing (guide body) 51 b isattached to the inside of the second outlet cover 113 b. The outerperiphery of another end 104 c of the pivot shaft performs an orbitingmotion while keeping in contact with the inner race 52 b of the secondbalance bearing. The relationship of another end 104 c of the pivotshaft and the inner race 52 b of the second balance bearing is alsodetermined by Formula 2. Therefore, deflection of another end 104 c ofthe pivot shaft due to centrifugal force is prevented.

A self-rotation prevention board 60 is provided between the right sideof the pivot bearing 103 and the paneling of the first fixed scroll 1 toprevent relative rotation therebetween. A self-rotation prevention pin61 is embedded at three locations in the outer periphery of theself-rotation prevention board 60. A self-rotation prevention bearing 62is provided on the paneling of the first fixed scroll 1. Theself-rotation prevention board 60, the self-rotation prevention pin 61and the self-rotation prevention bearing 62 constitute a self-rotationprevention means. The self-rotation prevention pin 61 performs anorbiting motion while keeping in contact with the inner race 63 of theself-rotation prevention bearing. If the outer diameter of theself-rotation prevention pin 61 is defined as d3, the inner diameter ofthe inner race 63 of the self-rotation prevention bearing is defined asD3 and the orbit radius of the pivot shaft 104 when this fluid machineis driven, is defined as ε and an inner gap of the bearing is defined asδ, then d3, D3, ε and δ are determined so as to satisfy Formula 3.

Similarly to the eighth embodiment of the present invention, thisembodiment configured as described above can produce four times as largeas the flow volume compared to a fluid machine provided with a singleset of the scroll part at one end of the casing 100.

Ninth Embodiment

FIG. 17 shows a ninth embodiment. The same components as the seventhembodiment employ the same symbols and names and the description is notrepeated. The third fixed scroll 3 is divided into two parts. The firstpaneling 3 e of the third fixed scroll and the second paneling 3 f ofthe third fixed scroll are integrally joined back to back. A gap isprovided at the center part between the first paneling 3 e of the thirdfixed scroll and the second paneling 3 f of the third fixed scroll. Aseal board 44 fixed to the pivot drive part 104 a is slidably fitted inthis gap. Both surfaces of the seal board 44 are sealed by a first seal45 attached to the first paneling 3 e of the third fixed scroll and asecond seal 46 attached to the second paneling 3 f of the third fixedscroll. By this seal, the through-hole 3 c of the third fixed scroll isobstructed halfway.

The first work chamber 21 and the second work chamber 22, which areformed by combination of the first fixed scroll wrap 1 a, the firstorbiting scroll wraps 11 a, 11 b and the third fixed scroll wrap 3 a,constitute a compressor. Further, the third work chamber 23 and thefourth work chamber 24, which are formed by combination of the thirdfixed scroll wrap 3 b, the second orbiting scroll wraps 12 a, 12 b andthe second fixed scroll wrap 2 a, constitute an expander.

Working fluid flows through an expander entrance 207 b provided at theoutlet cover 113 that is provided on the second fixed scroll. Theworking fluid enters the center part of the fourth work chamber 24through the through-hole 2 c of the second fixed scroll, also enters thethird work chamber 23 through the communication hole 12 c of the secondorbiting paneling, and expand while moving toward the outer periphery,when the working fluid applies an orbiting force to the second orbitingscroll 12. An expander exit 208 b is provided at the outer periphery ofthe second fixed scroll 2. The working fluid fully expanded isdischarged from the expander exit 208 b. A compressor inlet 207 a isprovided at the outer periphery of the first fixed scroll 1. Theentrance of a cooler (water heater) 121 is connected to the expanderexit 208 b, and the exit is connected to the compressor inlet 207 a. Theworking fluid cooled down to a low temperature by the cooler 121, entersthe first work chamber 21 and the second work chamber 23 and iscompressed while moving toward the inner periphery. The working fluidfully compressed jointly flows through the communication hole 11 c ofthe first orbiting paneling, enters the inside of the casing 100 throughthe through-hole 1 c of the first fixed scroll and is discharged to theoutside from the compressor outlet 208 a. The entrance of a heater(collector) 120 is connected to the compressor outlet 208 a, and theexit is connected to the expander entrance 207 b.

The working fluid discharged from the compressor outlet 208 a is heatedto high temperature by the heater 120, flowing into the expander throughthe expander entrance 207 b. In this process, the workload of theexpander becomes larger than power of the compressor, thus the expanderdrives the compressor. Also, the expander drives the pivot drive part104 a and pivot drives the pivot shaft 104. The pivot shaft 104 rotatesthe rotary shaft 102. The rotary shaft 102 rotates the attached rotor105, thereby an electromotive force is generated in the winding of thestator 106. As a result, electric power is generated at the winding.That is, this fluid machine can be used as a generator.

Generally, when driving the compressor using the expander, power istransmitted in the form of torque, and thus loss occurs at the bearingsupporting respective drive shafts. However, in this embodiment, theexpander and the compressor are attached to the common pivot drive part104 a, thereby power is transmitted in the form of load, therefore, noloss occurs between the expander and the compressor. Further, stablegases, which are unliquefied at room temperature such as air, nitrogen,helium, etc. are preferably used as working fluid.

Tenth Embodiment

FIG. 18 shows a tenth embodiment. This embodiment shows an example inwhich two of the four sets of work chambers are used as expanders andthe other two sets are used as blowers, thus applying this configurationto a system of fuel battery in the same scroll fluid machine as theninth embodiment.

A blower inlet 307 is provided at the outer periphery of the first fixedscroll 1. Air is taken in the first work chamber 21 and the second workchamber 22 through the blower inlet 307 and is compressed while movingtoward the inner periphery. Fully compressed air enters the inside ofthe casing 100 through the through-hole 1 c of the first fixed scroll,and is discharged to the outside through a blower outlet 308. Anexpander entrance 207 b is provided at the center of the second fixedscroll 2. The entrance of fuel battery 122 is connected to the bloweroutlet 308 while the exit is connected to the expander entrance 207 b.The exhaust air discharged from the fuel battery 122 yet keeps somewhathigh pressure, enters the center of the third work chamber and thefourth work chamber through the through-hole 2 c of the second fixedscroll and expands while moving toward the outer periphery, when the airapplies an orbiting force to the second orbiting scroll 12. An expanderexit 208 b is provided at the outer periphery of the second fixed scroll2. Fully expanded air is discharged from the expander exit 208 b. Inthis process, the workload of the expander supplements power of theblower driving the first orbiting scroll 11, thus energy is regeneratedas a total fuel battery system.

FIG. 19 shows a modified example of the tenth embodiment. FIG. 19 showsan example of the scroll fluid machine using the same structure as FIG.15, in which the four of the eight sets of work chambers are used asexpanders, and the other four sets of work chambers are used as blowers,thus applying this configuration to a system of fuel battery.

A blower inlet 307 is provided at the outer periphery of the fifth fixedscroll 5. Air is taken in the fifth work chamber 25, the sixth workchamber 26, the seventh work chamber 27 and the eighth work chamber 28through the blower inlet 307 and is compressed while moving toward theinner periphery. Fully compressed air passes through the through-hole 5c of the fifth fixed scroll and is discharged to the outside through theblower outlet 308 provided at the second outlet cover 113 b. An expanderentrance 207 b is provided at the center of the first outlet cover 113 aprovided on the second fixed scroll 2. The entrance of fuel battery 122is connected to the blower outlet 308 while the exit is connected to theexpander entrance 207 b. The exhaust air discharged from the fuelbattery 122 yet keeps somewhat high pressure, enters the center of thefourth work chamber 24, the fourth work chamber 23, the second workchamber 22 and the first work chamber 21 through the through-hole 2 c ofthe second fixed scroll and expands while moving toward the outerperiphery, when the air applies an orbiting force to the first orbitingscroll 11 and the second orbiting scroll 12. An expander exit 208 b isprovided at the outer periphery of the second fixed scroll 2. Fullyexpanded air is discharged from the expander exit 208 b. In thisprocess, the workload of the expander supplements power of the blowerdriving the third orbiting scroll 13 and the fourth orbiting scroll 14,thus energy is regenerated as a total fuel battery system.

FIG. 20 shows modified examples of the ninth or the tenth embodiments. Aheat insulating plate 3 g is sandwiched between the first paneling 3 eof the third fixed scroll and the second paneling 3 f of the third fixedscroll. If supplied with high-temperature fluid heated as high aspossible, the expander can increase generated power. In contrast, iflow-temperature fluid cooled down as low as possible is taken in, thecompressor can reduce consumed power. Thus, high-temperature fluidheated as high as possible by a heater 120 is taken in the work chambers23, 24 through the expander entrance 207 b and the through-hole 2 c ofthe second fixed scroll. On the other hand, low-temperature fluidsufficiently cooled down by the cooler 121 is taken in the work chambers21, 22 through the compressor inlet 207 a.

In this case, for the compressor, the temperature is comparativelylowered in the first fixed scroll 1, the first orbiting scroll 11, thethird fixed scroll wrap 3 a and the first paneling 3 e of the thirdfixed scroll. Further, for the expander, the temperature iscomparatively raised in the second fixed scroll 2, the second orbitingscroll 12, the third fixed scroll wrap 3 b and the second paneling 3 fof the third fixed scroll. However, if a large amount of heat transferoccurs due to heat conduction between the third fixed scroll wrap 3 a ofthe compressor and the third fixed scroll wrap 3 b of the expander, thethird fixed scroll wrap 3 a cannot keep the low temperature, thus theconsumed power of the compressor is increased, while the third fixedscroll wrap 3 b cannot keep the high-temperature, thus the generatedpower of the expander is lowered. That is, production of electricitygenerated as power difference between the expander and the compressor islowered.

As such, in this embodiment, a heat insulating plate 3 g is insertedbetween the first paneling 3 e of the third fixed scroll of thecompressor and the second paneling 3 f of the third fixed scroll of theexpander, thereby the amount of heat transfer due to heat conduction isreduced therebetween. Thereby, production of electricity generated aspower difference between the expander and the compressor cannot belowered.

Eleventh Embodiment

FIG. 21 shows an eleventh embodiment. The same parts as those in thesecond embodiment employ the same symbols and names and the descriptionis not repeated. The outlet cover 113 is attached to the outside face ofthe paneling of the second fixed scroll 2. A balance bearing (guidebody) 51 is attached to the inside of the outlet cover 113. A rotationalcylinder 80 is integrally attached to the inner race 52 of the balancebearing. A fan shaft 81 is integrally attached to the rotationalcylinder 80. A fan 82 is attached to the fan shaft 81. The outerperiphery of one end 104 b of the pivot shaft performs an orbitingmotion while keeping in contact with the inner surface of the rotationalcylinder 80. As such, the rotational cylinder 80 rotates along with thebalance bearing inner race 52 and the fan shaft 81 also rotates, thusthe fan 82 rotates. The rotational cylinder 80 is sealed between theinside and the outside with a seal ring 83 attached to the outlet cover113. Thus, in the case of the compressor, fluid is taken in through theinlet 107, compressed in the first work chamber 21 and the second workchamber 22, flows in the casing 100 through the first fixed scrollthrough-hole 1 c, and is discharged to the outside through the outlet108. When the fan 82 rotates, outside air is taken in through the inlet84, blown against the outside surface of the second fixed scroll 2, andis discharged through an exhaust outlet 85 after the second fixed scroll2 is cooled down. According to this configuration, the fan 82 rotatesbased on the orbiting motion of the pivot shaft 104 without a specificdrive device, for example, a motor, etc, cooling down the second fixedscroll 2. Therefore, the number of parts for the scroll fluid machinecan be reduced and the cost is saved.

FIGS. 22 to 24 show a method of attaching the orbiting scroll to thepivot drive part 104 a or the second pivot drive part 104 d in all theembodiments. The cross-section of the pivot drive part 104 a and thesecond pivot drive part 104 d has a noncircular shape. The holes openedin the center of the orbiting scroll 10 and the first to fourth orbitingscrolls 11, 12, 13 and 14, which are fitted to the pivot drive part 104a and the second pivot drive part 104 d, also have the same noncircularshapes. The cross-section of the pivot drive part and the hole of theorbiting scroll have a triangularly curved shape in the example shown inFIG. 22, a circular shape partially having a flat cut in the exampleshown in FIG. 23, and a rectangular shape in the example shown in 24.With the fit-in shape formed like this, the pivot drive part 104 a andthe second pivot drive part 104 d do not rotate relative to the orbitingscroll. Accordingly, if the self-rotation of the pivot shaft 104 isprevented, the self-rotation of the orbiting scrolls 10, 11, 12, 13 and14 can be prevented as well.

Further, the pivot drive part 104 a or the second pivot drive part 104 dis loosely fitted in the hole of the orbiting scroll. Thus, the orbitingscrolls 10, 11, 12, 13 and 14 can move in the axis direction on thepivot drive part 104 a or the second pivot drive part 104 d. Thus, evenif the pivot shaft 104 changes in dimension due to heat expansion, theorbiting scrolls 10, 11, 12, 13 and 14 are not subjected a load in theaxis direction. The orbiting scrolls 10, 11, 12, 13 and 14 arepositioned sandwiched by the fixed scrolls with a slight gap providedbetween a tip of each wrap and the paneling surface. As such, the tip ofwraps is not subjected to excessive force, thereby loss, wear, galling,etc. due to friction of the tip of wraps can be prevented.

Twelfth Embodiment

FIGS. 25 and 26 show a twelfth embodiment. In FIG. 25, a self-lubricantcylinder member 116 is attached to the inner race 112 of theself-rotation prevention bearing. The self-rotation prevention pin 110performs an orbiting motion while keeping in contact with the innersurface of the cylinder member 116. In this case, if the outer diameterof the self-rotation prevention pin 110 is defined as d1, the innerdiameter of the cylinder member 116 is defined as D1 and the orbitradius of the pivot shaft 104 when this fluid machine is driven, isdefined as ε and an inner gap of the bearing is defined as δ, then d1,D1, ε and δ are determined so as to satisfy Formula 1.

In FIG. 26, a self-lubricant cylinder member 53 is attached to the innerrace 52 of the balance bearing. One end 104 b of the pivot shaft oranother end 104 c of the pivot shaft performs an orbiting motion whilekeeping in contact with the inner surface of the cylinder member 53. Inthis case, if the outer diameter of one end 104 b or another end 104 cof the pivot shaft is defined as d2, the inner diameter of the cylindermember 53 is defined as D2 and the orbit radius of the pivot shaft 104when this scroll fluid machine is driven, is defined as ε and an innergap of the bearing is defined as δ, then d2, D2, ε and δ are determinedso as to satisfy Formula 2.

The material generally referred to as dry bearing or non-lubricantbearing is suitable for the cylinder member 116 or 53. The examples ofthe material include a resin containing component such astetrafluoroethylene, which is self-lubricant and has superiorslidability, metal coated with this resin, resin or sintered metalimpregnated with oil, resin or metal impregnated or coated withmolybdenum disulfide.

With this configuration, lubrication of the contact surface between thecylinder member 116 and the self-rotation prevention pin 110 isimproved, and wear of the self-rotation prevention pin 110 can bereduced. Otherwise, lubrication of the contact surface between thecylinder member 53 and another end 104 c of the pivot shaft is improved,and thus wear of another end 104 c of the pivot shaft can be reduced.

Thirteenth Embodiment

FIG. 27 shows a thirteenth embodiment. A sealing 48 is attached to bothsurfaces in the center part 10 d of the orbiting scroll. The sealing 48has a diameter such that it does not run over to the through-hole 1 c ofthe first fixed scroll and the through-hole 2 c of the second fixedscroll, even if the orbiting scroll 10 performs an orbiting motion. Thesealing 48 slides on the bottom land of the first fixed scroll 1 and thesecond fixed scroll 2, sealing the work chambers 21 and 22 from theoutside. An outlet 108 is provided on the paneling part of the secondfixed scroll 2, communicating with the work chamber in the center part.Further, the communication hole 10 c of the orbiting paneling isprovided in the center part of the paneling of the orbiting scroll 10.As such, the fluid taken in through the inlet 107 and compressed in thework chambers 21 and 22 is discharged to the outside through the outlet108 without escaping to the outside from the through-hole 1 c of thefirst fixed scroll and the through-hole 2 c of the second fixed scroll.Although a cover 117 is attached to the fixed scroll 2, fluid does notflow into the inside of the cover. According to the thirteenthembodiment, the self-rotation prevention bearing (guide body) 111 is notin the fluid route. As such, the self-rotation prevention bearing (guidebody) 111 is not subjected to high temperature, and is not corroded evenwhen handling corrosive fluid.

INDUSTRIAL APPLICABILITY

In the conventional structure of the pivot drive mechanism, the tip ofan orbiting drive shaft is displaced by a centrifugal force athigh-speed rotation, causing the orbiting scroll wrap to contact tightlyto the fixed scroll wrap, thereby wear and galling of the wrap occur ornoise occurs. This problem is solved by the present invention, therebythe scroll fluid machine can be downsized with specification ofhigh-speed rotation. Therefore, the present invention is likely to beused for a device such as a vacuum pump, a blower used for a fuelbattery, a refrigeration compressor, a home and packagedair-conditioner, an industrial air compressor, etc. that are desired tobe compact.

1. A scroll fluid machine, comprising: a rotary shaft, having a statorfixed to a casing, rotatably supported by said casing; a rotor fixed tosaid rotary shaft; a pivot shaft eccentrically and rotatably supportedby said rotary shaft; a self-rotation prevention means for preventingthe self-rotation of said pivot shaft; and a work part configured withcombination of an orbiting scroll, fitted in a pivot drive part of saidpivot shaft, having spiral wraps on both surfaces, and a pair of fixedscrolls fixed to one end of said casing, wherein: said pivot shaftpasses through said work part; a fixed scroll located at the most outerpart has a guide body; and one end of said pivot shaft performs anorbiting motion guided by said guide body.
 2. The scroll fluid machineaccording to claim 1, wherein: said guide body is a self-rotationprevention guide fixed to said fixed scroll located at the most outerpart; and said self-rotation prevention means is configured with aself-rotation prevention board fixed to one end of said pivot shaft,self-rotation prevention pins attached to more than two locations ofsaid self-rotation prevention board, and said self-rotation preventionguide; and said self-rotation prevention pin performs an orbiting motionwhile keeping in contact with the inner surface of said self-rotationprevention guide.
 3. The scroll fluid machine according to claim 2,wherein: said self-rotation prevention guide is a self-rotationprevention bearing; and said self-rotation prevention pin performs anorbiting motion while keeping in contact with the inner surface of theinner race of the self-rotation prevention bearing.
 4. The scroll fluidmachine according to claim 2, wherein: said self-rotation preventionguide is a self-rotation prevention slide member having a circular hole,and; said self-rotation prevention pin performs an orbiting motion whilekeeping in contact with the inner surface of the self-rotationprevention slide member.
 5. The scroll fluid machine according to claim2, wherein: said self-rotation prevention guide produces a reactionforce equivalent to the load radially produced at one end of said pivotshaft; thereby preventing said pivot shaft from being radiallydisplaced. 6-7. (not entered)
 8. The scroll fluid machine according toclaim 1, wherein: said guide body is a balance bearing, and; the outerperiphery of the pivot shaft tip performs an orbiting motion whilekeeping in contact with the inner race of said balance bearing providedin the center part of the fixed scroll located at the most outer part.9. The scroll fluid machine according to claim 8, wherein: said balancebearing produces a reaction force equivalent to the load radiallyproduced at one end of said pivot shaft, thereby preventing said pivotshaft from being radially displaced.
 10. The scroll fluid machineaccording to claim 8, wherein: said self-rotation prevention means isconfigured with a self-rotation prevention board attached to the otherend of said pivot shaft, self-rotation prevention pins attached to morethan two locations of the self-rotation prevention board, and aself-rotation prevention bearing fixed to the casing; and saidself-rotation prevention pin performs an orbiting motion while keepingin contact with the inner race of the self-rotation prevention bearing.11. The scroll fluid machine according to claim 8, wherein: saidself-rotation prevention means is configured with a self-rotationprevention board attached to the other end of said pivot shaft,self-rotation prevention pins attached to more than two locations of theself-rotation prevention board, and a self-rotation prevention slidemember, having a circular hole and fixed to the casing; and saidself-rotation prevention pin performs an orbiting motion while keepingin contact with the self-rotation prevention slide member.
 12. Thescroll fluid machine according to claim 8, wherein one end of said pivotshaft having contact with said inner race of the balance bearing has acurved surface in the axis direction.
 13. The scroll fluid machineaccording to claim 8, wherein: a cover insulating the work chamber fromoutside air is provided in the center part of the fixed scroll locatedat the most outer part, and an outlet is provided at a part of thecasing.
 14. A scroll fluid machine, comprising: a rotary shaft, having astator fixed to a casing, rotatably supported by said casing; a rotorfixed to said rotary shaft; a pivot shaft eccentrically and rotatablysupported by said rotary shaft; a self-rotation prevention means forpreventing the self-rotation of said pivot shaft; and a pair or pairs ofwork parts configured with combination of an orbiting scroll, fitted ina pivot drive part of said pivot shaft, having spiral wraps on bothsurfaces, and a fixed scroll, fixed to one end of said casing, havingspiral wraps, and a pair or pairs of work parts configured withcombination of an orbiting scroll, fitted in a second pivot drive partof said pivot shaft, having spiral wraps on both surfaces, and a fixedscroll, fixed to the other end of said casing, having spiral wraps,wherein: one end of said pivot shaft passes through said work part onone end side, a fixed scroll located at the most outer part on one endside has a guide body, and one end outer periphery of said pivot shaftperforms an orbiting motion guided by said guide body on one end side;and the other end of said pivot shaft passes through said work part onthe other end side, a fixed scroll located at the most outer part on theother end side has a guide body, and the other end outer periphery ofsaid pivot shaft performs an orbiting motion guided by said guide bodyon the other end side.
 15. The scroll fluid machine according to claim14, wherein: said guide body is a balance bearing or a self-rotationprevention means; said balance bearing is provided in the center part ofthe fixed scroll located at the most outer part at one side; the tipouter periphery of said pivot shaft performs an orbiting motion whilekeeping in contact with said inner race of the balance bearing; and saidself-rotation prevention means is configured with a self-rotationprevention board fixed to the other end of said pivot shaft,self-rotation prevention pins attached to more than two locations ofsaid self-rotation prevention board, and said self-rotation preventionguide fixed to the fixed scroll located at the most outer part locatedat the other side of said pivot shaft; and said self-rotation preventionpin performs an orbiting motion while keeping in contact with the innersurface of said self-rotation prevention guide.
 16. The scroll fluidmachine according to claim 15, wherein said self-rotation preventionguide is a self-rotation prevention bearing and said self-rotationprevention pin performs an orbiting motion while keeping in contact withthe inner surface of the inner race of the self-rotation preventionbearing.
 17. The scroll fluid machine according to claim 15, whereinsaid self-rotation prevention guide is a self-rotation prevention slidemember having a circular hole, and said self-rotation prevention pinperforms an orbiting motion while keeping in contact with the innersurface of the self-rotation prevention slide member. 18-19. (notentered)
 20. The scroll fluid machine according to claim 14, whereinsaid guide body is a balance bearing, and the outer periphery of bothends of the pivot shaft performs an orbiting motion while keeping incontact with the inner race of said balance bearing provided in thecenter part of the fixed scroll located at the most outer part at bothsides.
 21. The scroll fluid machine according to claim 20, wherein: saidself-rotation prevention means is configured with a self-rotationprevention guide fixed to the fixed scroll at the most inner side thatis fixed to one end or the other end of the casing, a self-rotationprevention board attached to said pivot shaft near the self-rotationprevention guide, and a self-rotation prevention pins attached to atleast two or more locations of the self-rotation prevention board; andthe self-rotation prevention pins perform an orbiting motion whilekeeping in contact with the inner surface of said self-rotationprevention guide.
 22. The scroll fluid machine according to claim 21,wherein said self-rotation prevention guide is a self-rotationprevention bearing, and said self-rotation prevention pins perform anorbiting motion while keeping in contact with the inner surface of theinner race of the self-rotation prevention bearing.
 23. The scroll fluidmachine according to claim 21, wherein said self-rotation preventionguide is a self-rotation prevention slide member having a circular hole,and said self-rotation prevention pins perform an orbiting motion whilekeeping in contact with the inner surface of the self-rotationprevention slide member.
 24. The scroll fluid machine according to claim21, wherein a cover insulating the work chamber from outside air isprovided in the center part of the fixed scroll located at the mostouter part, and an outlet is provided at a part of the casing.
 25. Ascroll fluid machine, comprising: (1) a rotary shaft, having a statorfixed to a casing, rotatably supported by said casing; (2) a rotor fixedto said rotary shaft; (3) a pivot shaft eccentrically and rotatablysupported by said rotary shaft; a self-rotation prevention means forpreventing the self-rotation of said pivot shaft; (4) a self-rotationprevention means for preventing the self-rotation of said pivot shaft;and (5) four sets of work chambers configured with combination of afixed scroll having wraps on one surface, an orbiting scroll havingwraps on both surfaces, a fixed scroll having wraps on both surfaces, anorbiting scroll having wraps on both surfaces, and a fixed scroll havingwraps on one surface, with the wraps combined with each other in thisorder, wherein: said two orbiting scrolls are attached in series to saidpivot shaft; a hole that allows said pivot shaft to pass through andperform an orbiting motion, is provided at the paneling of said threefixed scroll; a balance bearing is provided in the center part of thepaneling of the fixed scroll that is located at the most outer part; andthe outer periphery of the pivot shaft tip performs an orbiting motionwhile keeping in contact with the inner surface of the inner race ofsaid balance bearing.
 26. The scroll fluid machine according to claim25, wherein the phases of starting the inlet or the outlet are allshifted in said four sets of work chambers and the shifted amounts aremultiples of 90 degrees.
 27. The scroll fluid machine according to claim25, wherein: two sets of the work chambers on one side of said four setsof the work chambers are expanders, and the other two sets of the workchambers adjacently provided on the other side are compressors, and aseal mechanism sealing between the expander and the compressor isprovided at a through-hole of the pivot shaft in the center part of thepaneling of the fixed scroll that is located between said expander andsaid compressor, having wraps on both sides of the paneling.
 28. (notentered)
 29. The scroll fluid machine according to claim 25, wherein thepaneling is divided in the fixed scroll that is located in the middle ofsaid four sets of the work chamber, having wraps on both sides, and aheat insulating plate is inserted between said divided paneling.
 30. Thescroll fluid machine according to claim 1, wherein a seal mechanismsealing between the work chamber and the casing is provided in thecenter part of the paneling of the fixed scroll that is directlyconnected to the casing.
 31. The scroll fluid machine according to claim27, wherein said seal seals both surfaces of a disk integrally attachedto the pivot shaft with a ring-shaped sealing member.
 32. The scrollfluid machine according to claim 1, wherein an outlet cover configuringan outlet separating the outlet chamber from outside air is provided atthe paneling of the fixed scroll at the most outer side.
 33. (notentered)
 34. The scroll fluid machine according to claim 1, wherein thecross-section of a fitting part between a pivot drive part or a secondpivot drive part and a hole in the center part of the orbiting scroll,has a noncircular shape.
 35. The scroll fluid machine according to claim34, wherein the fitting parts of the pivot drive part or the secondpivot drive part and the hole of the center part of said orbitingscroll, are slidable to each other in the axis direction.
 36. The scrollfluid machine according to claim 2, wherein: if the outer diameter ofsaid self-rotation prevention pin provided at the self-rotationprevention board that is attached to one end of said pivot shaft, isdefined as d1, the inner diameter of the inner race of saidself-rotation prevention bearing or the inner diameter of saidself-rotation prevention slide member is defined as D1, and the orbitradius of the pivot shaft is defined as ε; then the difference betweenthe values of D1−d1 and 2ε is determined so as to be smaller than thebearing inner gap of said self-rotation prevention bearing.
 37. Thescroll fluid machine according to claim 8; wherein: if the outerdiameter of one end or the other end of said pivot shaft is defined asd2, the inner diameter of the inner race of said balance bearing isdefined as D2, and the orbit radius of the pivot shaft is defined as ε;then the difference between the values of D2−d2 and 2ε is determined soas to be smaller than the bearing inner gap of said balance bearing. 38.The scroll fluid machine according to claim 10, wherein: if the outerdiameter of said self-rotation prevention pin attached to theself-rotation prevention board that is attached to the other end or themiddle part of said pivot shaft, is defined as d3, the inner diameter ofthe inner race of said self-rotation prevention bearing or the innerdiameter of the self-rotation prevention slide member is defined as D3,and the orbit radius of the pivot shaft is defined as ε; then thedifference between the values of D3−d3 and 2ε is determined so as to besmaller than the bearing inner gap of said self-rotation preventionbearing.
 39. (not entered)